Thermodynamics

How can we find out how many microstates are accessible for a macrostate? (Remember, a macrostate is just any system whose thermodynamic qualities of P, V, T, H, etc. have been measured so the system is exactly defined.)

• How can we find out how many microstates are accessible for a macrostate? (Remember, a macrostate is just any system whose thermodynamic qualities of P, V, T, H, etc. have been measured so the system is exactly defined.)
• Fortunately, Ludwig Boltzmann gives us the answer in
• S = kB ln W,
• where S is the value of entropy in joules/mole at T,
• kB is Boltzmann's constant of 1.4 x 10-23 J/K and
• W is the number of microstates, called the thermodynamic probability.

• Spontaneous events occur only when energy spreads out and entropy increases.

Entropy increase predicts what physical and chemical events will happen spontaneously - in the lab and everywhere in the world since its beginning.

• Entropy increase predicts what physical and chemical events will happen spontaneously - in the lab and everywhere in the world since its beginning.
• That's why entropy increases can be called "time's arrow". Energy continually disperses and spreads out in all natural spontaneous events. (It's our experience all our lives with spontaneous natural events that gives us our psychological feeling of "time" passing

The internal energy of a thermodynamic system, or a body with well-defined boundaries, denoted by U, or sometimes E, is the total of the kinetic energy due to the motion of molecules (translational, rotational, vibrational) and the potential energy associated with the vibrational and electric energy of atoms within molecules or crystals.

• The internal energy of a thermodynamic system, or a body with well-defined boundaries, denoted by U, or sometimes E, is the total of the kinetic energy due to the motion of molecules (translational, rotational, vibrational) and the potential energy associated with the vibrational and electric energy of atoms within molecules or crystals.
• It includes the energy in all of the chemical bonds, and the energy of the free, conduction electrons in metals.